Compressed air introduced into the top fitting forces the sample out of the bottom fitting into a collecting bottle. The rubber Duckbill acts like a check valve and prevents air from escaping back through inlet. When the top fitting is vented to the atmosphere, hydrostatic pressure within the liquid bath forces a fresh sample up the vertical inlet and through the Duckbill’s slit until the body is filled above the vent fitting, but below top of the Duckbill. A trapped air pocket in the dome keeps the sampler from filling completely. The sampler is now ready for a burst of compressed air to ‘call in’ another sample to the collecting station. Reverse leakage of the sample back through the Duckbill is impossible.

Flow ProportionalWith the two external control terminals jumpered, a dial sets the time between samples. With the jumper removed and an external normally open (N.O.) contact connected, momentary closures cause one sample to be extracted for every closure. This gives samples proportional to flow when connected to a Flow Meter Totalizer Integrator Switch. In addition, maintaining external contact closed turns the sampler clock ON, and the clock continues to run and extract samples at time interval set on dial until maintained closure is broken.

Remote Start-up
When connected to a 24-hour timer, delayed start-up or intermittent operation can be accomplished. If connected to a Float Switch, the sampler can be turned on when liquid level rises, for example sampling storm water runoff. When connected to pH or other type meter, samples can be extracted only when a pollution parameter is out of limits. Remote start-up by radio or telephone signals is another possibility for this multipurpose controller.